On Fri, Mar 23, 2018 at 02:47:23PM +0000, Michal Wajdeczko wrote:
> Instead of returning small data in response status dword,
> GuC may append longer data as response message payload.
> If caller provides response buffer, we will copy received
> data and use number of received data dwords as new success
> return value. We will WARN if response from GuC does not
> match caller expectation.
>
> v2: fix timeout and checkpatch warnings (Michal)
>
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx>
> Cc: Oscar Mateo <oscar.mateo@xxxxxxxxx>
> Cc: Michel Thierry <michel.thierry@xxxxxxxxx>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_guc_ct.c | 137 ++++++++++++++++++++++++++++++++----
> drivers/gpu/drm/i915/intel_guc_ct.h | 5 ++
> 2 files changed, 128 insertions(+), 14 deletions(-)
>
[SNIP]
> @@ -418,13 +499,15 @@ static int ctch_send(struct intel_guc *guc,
> static int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len,
> u32 *response_buf, u32 response_buf_size)
> {
> - struct intel_guc_ct_channel *ctch = &guc->ct.host_channel;
> + struct intel_guc_ct *ct = &guc->ct;
> + struct intel_guc_ct_channel *ctch = &ct->host_channel;
> u32 status = ~0; /* undefined */
> int ret;
>
> mutex_lock(&guc->send_mutex);
>
> - ret = ctch_send(guc, ctch, action, len, &status);
> + ret = ctch_send(ct, ctch, action, len, response_buf, response_buf_size,
> + &status);
> if (unlikely(ret < 0)) {
> DRM_ERROR("CT: send action %#X failed; err=%d status=%#X\n",
> action[0], ret, status);
> @@ -503,8 +586,13 @@ static int ctb_read(struct intel_guc_ct_buffer *ctb, u32 *data)
> static int ct_handle_response(struct intel_guc_ct *ct, const u32 *msg)
> {
> u32 header = msg[0];
> + u32 fence = msg[1];
> u32 status = msg[2];
> u32 len = ct_header_get_len(header) + 1; /* total len with header */
> + u32 payload_len = len - 3; /* len<3 is treated as protocol error */
Magic numbers, please ether define 3 as min payload length or hide this behind
macro.
> + struct ct_request *req;
> + bool found = false;
> + unsigned long flags;
>
> GEM_BUG_ON(!ct_header_is_response(header));
>
> @@ -518,8 +606,29 @@ static int ct_handle_response(struct intel_guc_ct *ct, const u32 *msg)
> DRM_ERROR("CT: corrupted response %*phn\n", 4*len, msg);
> return -EPROTO;
> }
> + spin_lock_irqsave(&ct->lock, flags);
Isn't this called from the irq? We can use plain spin_lock here.
> + list_for_each_entry(req, &ct->pending_requests, link) {
> + if (req->fence != fence) {
> + DRM_DEBUG_DRIVER("CT: request %u awaits response\n",
> + req->fence);
> + continue;
Is this expected?
In other words - do we expect out of order responses?
Can we extract this into a helper (find request)?
-Michał
> + }
> + if (unlikely(payload_len > req->response_len)) {
> + DRM_ERROR("CT: response %u too long %*phn\n",
> + req->fence, 4*len, msg);
> + payload_len = 0;
> + }
> + if (payload_len)
> + memcpy(req->response_buf, msg + 3, 4*payload_len);
> + req->response_len = payload_len;
> + WRITE_ONCE(req->status, status);
> + found = true;
> + break;
> + }
> + spin_unlock_irqrestore(&ct->lock, flags);
>
> - /* XXX */
> + if (!found)
> + DRM_ERROR("CT: unsolicited response %*phn\n", 4*len, msg);
> return 0;
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_guc_ct.h b/drivers/gpu/drm/i915/intel_guc_ct.h
> index 595c8ad..905566b 100644
> --- a/drivers/gpu/drm/i915/intel_guc_ct.h
> +++ b/drivers/gpu/drm/i915/intel_guc_ct.h
> @@ -71,10 +71,15 @@ struct intel_guc_ct_channel {
> /** Holds all command transport channels.
> *
> * @host_channel: main channel used by the host
> + * @lock: spin lock for pending requests list
> + * @pending_requests: list of pending requests
> */
> struct intel_guc_ct {
> struct intel_guc_ct_channel host_channel;
> /* other channels are tbd */
> +
> + spinlock_t lock;
> + struct list_head pending_requests;
> };
>
> void intel_guc_ct_init_early(struct intel_guc_ct *ct);
> --
> 1.9.1
>
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